1935 temp sender

[danliveshere]

I'm wanting to treat my 35 temp sender tube I'm not sure about using a rust converter on the spiral tube unit in case of a bad reaction to the copper tube itself. The unit itself works fine( although there is a staining inside the glass gauge which makes it hard to see the liquid when it's cold but I can see the liquid easily as it heats up and the level gets above the stain). How have others treated their tube when restoring their car thanks Dan